Anode-free solid state battery having a pseudo-solid lithium gel layer

ABSTRACT

In various embodiments, an anti-dendrite anode-free solid-state battery (SSB) are presented. The SSB can include a cathode layer; an anode current collector layer; and a lithium gel separator layer between the cathode layer and the anode current collector layer. An anti-dendrite layer may also be present located between the lithium gel separator layer and the anode current collector layer. The anti-dendrite layer can help discourage dendrite formation.

BACKGROUND

During charging of a lithium ion battery, lithium ions migrate frombattery's cathode to the battery's anode through a separator locatedbetween the cathode and anode. Through a process called intercalation,lithium ions become inserted into the material functioning as the anode.During this charging process, lithium ions may also plate onto a surfaceof the anode facing the separator. The nucleation energy associated withthe anode may encourage lithium ions to plate on top of other lithiumthat has already plated onto the anode (rather than plating in a roughlyeven film across the surface of the anode). These pools of lithium canform dendrites. A dendrite can be a protrusion of lithium metal thatextends away from the surface of the anode towards the separator. Overtime (e.g., through multiple charge and discharge cycles), dendrites maygrow to such a length that the dendrite pierces the separator anddirectly electrically connects (i.e. short circuits) the cathode withthe anode. Such an electrical connection can result in destruction ofthe battery and possibly serious side-effects, such as overheating andfire.

SUMMARY

Various embodiments are described related to an anti-dendrite anode-freesolid-state battery. In some embodiments, an anti-dendrite anode-freesolid-state battery is described. The battery may comprise a cathodelayer. The battery may comprise an anode current collector layer. Thebattery may comprise a lithium gel separator layer between the cathodelayer and the anode current collector layer. The battery may comprise ananti-dendrite layer located between the lithium gel separator layer andthe anode current collector layer. The anti-dendrite layer maydiscourage dendrite formation.

Embodiments of such a device may include one or more of the followingfeatures: the lithium gel separator layer may comprise a first adhesivelayer. The lithium gel separator layer may comprise a second adhesivelayer. The lithium gel may comprise a lithium gel layer located betweenthe first adhesive layer and the second adhesive layer. The lithium gelseparator layer may comprise a scaffolding material, a salt, a solvent,and at least one additive. The at least one additive may comprise apolymer and a cross-linker. The first adhesive layer and the secondadhesive layer may comprise a lithium-conductor ceramic. A presence ofthe anti-dendrite layer may cause a nucleation barrier to be decreasedin energy for lithium ions to deposit onto the anode current collectorlayer. The anti-dendrite layer may be between 0.05 micrometers and 10micrometers in thickness. The anti-dendrite layer may comprise one ormore materials selected from the group consisting of carbon black,acetylene black, ketchen black, silver, zinc, gold, bismuth, tin,polyvinylidene fluoride (PVDF), polymide (PI), polyacrylic acid (PAA),and carboxymethyl cellulose styrene-butadiene rubber (CMC-SBR). A firstamount of adhesion between the anti-dendrite layer and the anode currentcollector layer may be less than a second amount of adhesive between theanti-dendrite layer and the lithium gel separator layer. The anodecurrent collector layer may be copper. The device may further comprisean aluminum cathode current collector.

In some embodiments, a method for creating an anti-dendrite anode-freesolid-state battery is described. The method may comprise depositing ananti-dendrite layer onto an anode current collector layer. The methodmay comprise creating a lithium-gel separator layer. The method maycomprise layering a cathode current collector layer onto a cathodelayer. The method may include layering the lithium-gel separator layerbetween the anti-dendrite layer and the cathode layer, thereby creatinga layered battery stack of: the cathode current collector layer, thecathode layer, the lithium-gel separator layer, the anti-dendrite layer,and the anode current collector layer. The method may comprise packagingthe layered battery stack in a flexible pouch cell. The method maycomprise applying heat and pressure to the layered battery stack withinthe flexible pouch cell.

Embodiments of such a method may include one or more of the followingfeatures: creating the lithium-gel separator layer may compriseattaching a first adhesive layer to a scaffolding. The method maycomprise attaching a second adhesive layer to the scaffolding. Themethod may include permeating a liquid electrolyte into the scaffolding.The liquid electrolyte may comprise: a lithium salt; a solvent; and atleast one additive. The at least one additive may comprise a polymer anda cross-linker. Applying the heat may cause the liquid electrolyte tobecome a gel. A presence of the anti-dendrite layer may cause anucleation barrier to be decreased in energy for lithium ions to depositonto the anode current collector layer. The anti-dendrite layer may bebetween 0.05 micrometers and 10 micrometers in thickness. The method mayfurther comprise compressing the flexible pouch cell in a jig press. Themethod may further comprise charging and discharging the layered batterystack within the jig press. The anti-dendrite layer may comprise one ormore materials selected from the group consisting of carbon black,acetylene black, ketchen black, silver, zinc, gold, bismuth, tin,polyvinylidene fluoride (PVDF), polymide (PI), polyacrylic acid (PAA),and carboxymethyl cellulose styrene-butadiene rubber (CMC-SBR).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an embodiment of a layer stack of an anode-freesolid-state battery having a lithium gel separator layer and ananti-dendrite layer.

FIG. 2 illustrates another embodiment of a layer stack of an anode-freesolid-state battery having lithium gel separator layers andanti-dendrite layers.

FIG. 3A illustrates an embodiment of a lithium gel separator layer beingformed using heat.

FIG. 3B illustrates an embodiment of a method for creating a lithium gelseparator layer.

FIG. 4 illustrates an embodiment of a method for manufacturing apouch-style battery cell that contains an anode-free solid-state batteryhaving a lithium gel separator layer and an anti-dendrite layer.

FIG. 5 illustrates an embodiment of a cylindrical battery press system.

FIGS. 6A and 6B illustrates an embodiment of a method for creating acylindrical anti-dendrite anode-free solid-state battery.

FIG. 7 illustrates an embodiment of a layer stack of an anode-freesolid-state battery having a lithium gel separator layer, ananti-dendrite layer, and a interfacial bonding layer.

FIG. 8 illustrates an embodiment of a layer stack of an anode-freesolid-state battery that indicates relative amounts of adhesion betweenvarious layers.

FIG. 9 illustrates an embodiment of a layer stack of an anode-freesolid-state battery being charged in which lithium is being depositedonto the interfacial bonding layer.

FIG. 10 illustrates an embodiment of a method for manufacturing apouch-style battery cell that contains a solid-state battery having alithium gel separator layer, an anti-dendrite layer, and an interfacialbonding layer.

DETAILED DESCRIPTION

Introduction of an anti-dendrite layer in combination with a lithium gelseparator layer can inhibit the growth of dendrites while not increasingthe thickness of the battery cell by a large amount. An anti-dendritelayer may be coated directly onto an anode current collector of ananode-free solid state battery (SSB). In an anode-free SSB, the anodecurrent collector, which can be a copper foil, may effectively functionas both the anode and the anode current collector. The anti-dendritelayer may decrease the nucleation energy needed for lithium ions todeposit as lithium metal onto the surface of the anode current collectorthat is in contact with the anti-dendrite layer. Rather than lithiumions tending to plate on top of lithium metal that has already platedonto the surface of the anode current collector (thus causing pools,which can lead to dendrite), lithium may tend to deposit in a roughlyeven film across the surface of the anode current collector.

The anti-dendrite layer may be in direct contact with a lithium gelseparator layer. The lithium gel separator layer may serve multiplefunctions. First, the lithium gel separator layer can function as asolid-state electrolyte to facilitate movement of lithium ions betweenthe cathode and the anode. The lithium gel separator layer also servesas a separator to prevent a direct electrical connection between thecathode and anode. The lithium gel separator layer further can havecharacteristics that further inhibit dendrite growth.

Further detail regarding such embodiments and additional embodiments isprovided in relation to the figures. FIG. 1 illustrates an embodiment ofa layer stack 100 of an anode-free solid-state battery having a lithiumgel separator layer and an anti-dendrite layer. Layer stack 100 caninclude: cathode current collector 110; cathode 120; lithium gelseparator layer 130; anti-dendrite layer 140; and anode currentcollector 150.

Cathode current collector 110 may be a conductive film that is layeredwith cathode 120. Cathode current collector 110 may, for example, be analuminum foil. Other forms of conductive foils are possible. Cathode 120may, for example, be NCA (Nickel-Cobalt-Aluminum Oxide) or NCM(nickel-manganese-cobalt).

Cathode 120 may have a first surface in direct contact with cathodecurrent collector 110, an opposite surface of cathode 120 can be indirect contact with lithium gel separator layer 130. Lithium gelseparator layer 130 can function as a solid-state electrolyte (in theform of a gel) to facilitate movement of lithium ions between cathode120 and anode current collector 150. Lithium gel separator layer 130also serves as a separator to prevent a direct electrical connectionbetween cathode 120 and anode current collector 150. Lithium gelseparator layer 130 can have characteristics that further inhibitdendrite growth. Lithium gel separator layer 130 may be initially atleast partially in liquid form. After assembly, a process may be appliedto convert the liquid to a gel form. Such a process may involve theapplication of pressure, heat, or both. Further detail regarding lithiumgel separator layer 130 is provided in relation to FIG. 3A.

Lithium gel separator layer 130 may have a first surface in directcontact with cathode 120. A second surface opposite the first surface oflithium gel separator layer 130 may be in direct contact withanti-dendrite layer 140. Anti-dendrite layer 140 may have several keycharacteristics: First, anti-dendrite layer 140 may decrease thenucleation energy necessary for lithium ions to plate as lithium metalon the surface of anode current collector 150 in direct contact withanti-dendrite layer 140. By decreasing the nucleation energy, it may bemore likely that lithium ions will deposit directly onto anode currentcollector 150 rather than “pooling” or depositing onto lithium metalthat has already plated on anode current collector 150.

A second key characteristic of anti-dendrite layer 140 is that an amountof adhesion between anti-dendrite layer 140 and anode current collector150 is less than an amount of adhesion between anti-dendrite layer 140and lithium gel separator layer 130. By adhesion being less between thesurfaces of anti-dendrite layer 140 and anode current collector 150,lithium is encouraged to plate between anti-dendrite layer 140 and anodecurrent collector 150 as opposed to between lithium gel separator layer130 and anti-dendrite layer 140.

Anti-dendrite layer 140 may be relatively thin. For instance,anti-dendrite layer 140 may be between 0.05 μm and 10 μm. In someembodiments, anti-dendrite layer 140 may be deposited as a film on asurface of anode current collector 150. Anti-dendrite layer 140 may bemade of one or more of the following materials: carbon black; acetyleneback black; silver; zinc; gold; bismuth; tin; polyvinylidene fluoride(PvDF); polymide (PI); polyacrylic acid (PAA); and carboxymethylcellulose styrene-butadiene rubber (CMC-SBR). Anti-dendrite layer 140may also be formed using alloys of silver, zinc, gold, bismuth, and tin.While anti-dendrite layer 140 may be formed from a single type ofmaterial; multiple materials indicated may be used to form anti-dendritelayer 140.

Anode current collector 150 may have a first surface in contact withanti-dendrite layer 140. Anode current collector 150 can function asboth the anode and the anode current collector. In some embodiments,anode currently collector 150 is a conductive foil, such as a copperfoil. Without anti-dendrite layer 140 being present, anode currentcollector 150 may exhibit a higher nucleation energy that tends to causelithium to pool rather than deposit as a film during charging of thebattery cell.

FIG. 2 illustrates another embodiment of a layer stack 200 of ananode-free solid-state battery having lithium gel separator layers andanti-dendrite layers. In some embodiments, multiple sets of layers maybe layered together to increase the charge capacity of the battery cell.In the illustrated embodiment of FIG. 2, layers 110 through 150 are asdetailed in relation to FIG. 1. Additionally, anti-dendrite layer 210 islayered on an opposite side of anode current collector 150 fromanti-dendrite layer 140. A second lithium gel separator layer 202 is indirect contact with anti-dendrite layer 210. Further, cathode 230 andcathode current collector 240 are layered against lithium gel separatorlayer 220. Additional layers may be added in the same manner as detailedin relation to FIG. 2. For instance, below cathode current collector 240may be another cathode, followed by another lithium gel separator layer,etc. For instance many sets of layers may be added to increase thecharge capacity of the battery cell. While FIG. 1 shows a single stackset and FIG. 2 illustrates a double stack set; other embodiment mayinclude may more stacks, such as 16 or more. Such layers, once together,may be sealed as part of a pouch-style battery cell.

FIG. 3A illustrates an embodiment of a lithium gel separator layer beingformed using heat. FIG. 3B, detailed herein in parallel with FIG. 3A,illustrates an embodiment of a method for creating a lithium gelseparator layer. The lithium gel separator layer may function as aphase-changing electrolyte, which can be used in a solid state battery.A lithium gel separator layer, such as lithium gel separator layer 130,can include multiple sublayers and may be created using heat. Pressuremay also be used to increase the surface area of interfaces betweenlayers of the lithium gel separator layer. First, a non-reactivescaffold may be formed at block 350. For example, scaffolding material305 may be polyethylene (PE) or polyethylene oxide (PEO). Scaffoldingmaterial 305 may be permeable such that a liquid, such as an electrolyteliquid can be permeated, injected, or otherwise introduced toscaffolding material 305. The physical structure of scaffolding material305 may create gaps that can be filled with liquid. For instance,scaffolding material 305 may have a porosity of between 10% and 90%,into which a liquid can be introduced. The specific physical structuremay be honeycomb structure, spider-web structure, or some other patternor random porous physical structure that allows liquid to fill emptyspaces within scaffolding material 305. The scaffolding layer maybetween 1 μm and 100 μm thick. In some embodiments, the scaffoldinglayer is 15 μm thick.

At block 355, a first adhesive layer may be attached to the non-reactivescaffold. At block 360, a second adhesive layer may be attached to anopposite side of the non-reactive scaffold. Therefore, scaffoldingmaterial 305 may be located between two adhesive layers 310. Together,these three layers may form dry separator layer 300 in which anelectrolyte has not yet been introduced. Each of adhesive layers 310 mayinclude either PvDF, PI, PAA, or CMC-SBR. Such materials can function asan adhesive bonder. Therefore, adhesive layers 310 can serve to increasethe amount of adhesion between scaffolding material 305, cathode 120,and anti-dendrite layer 140. An amount of adhesion between lithium gelseparator layer 130 and anti-dendrite layer 140, at least in part due toan adhesion layer, may be greater than an amount of adhesion betweenanti-dendrite layer 140 and anode current collector 150.

In some embodiments, a ceramic may be added to one or both adhesivelayers that improves lithium ion transport and can help discouragedendrite formation. Such ceramics can include: MgO, PZT, BaTiO3, SBT,BFO, LATSPO, LISICON, LICGC, LAGP, LLZO, LZO, LAGTP, LiBETI, LiBOB,LiTf, LiTF, LLTO, LLZP, LTASP, and LTZP. Each of adhesive layers 310 maybe between 1-500 um in thickness. Using ceramics within the adhesivelayers can decrease ionic-conductivity. Using a Li-ion conductor ceramicmay still decrease ionic-conductivity (compared with liquid), but cansecure higher ionic-conductivity compared with other ceramics. However,the advantage of a ceramic being able to prevent a short-circuit and todecrease overall cell failure rate may out-weigh the drawback of thedecreased ionic conductivity.

At block 365, a liquid electrolyte mixture may be created. The liquidelectrolyte mixture may include: a lithium salt; a solvent; andadditives. The salt may be LIFSI, LITFSI, or LiPF6. The concentration ofthe salt may be between 1.0 to 4.0 mole per liter. The lithium salt mayallow the lithium liquid to function as an electrolyte. The solvent maybe: dimethyl carbonate (DMC), dimethoxyethane (DME), diethyl carbonate(DEC), dioxolane (DOL), bis trifluoroethyl ether (BTFE), ehtyl methylcarbonate (EMC), or ethylene carbonate (EC). The solvent may function todissolve the salt.

The additives may include the compounds within the lithium liquid thatcauses a transition from a liquid to a gel when heat is applied.Generally, the additives comprise a polymer and cross-linker. When heatof, for example, between 60° C. and 150° C. is applied to the additive,the cross-linker ignites and causes further polymerization of thepolymer and the solvent. Since the lithium salt is evenly distributedthroughout the solvent, when the gel is formed, the lithium salt will beevenly distributed throughout the gel. The one or more additives mayinclude CsPF6, FEC (fluoroethylene carbonate), polycarbonate (PC), orLiNO3. The additive may have a concentration of 0.01-4.0 moles perliter. The additives, includes the polymer additive and the cross-linkeradditive may be mixed into the lithium liquid before the lithium liquidis permeated throughout the non-reactive scaffolding.

One possible combination of lithium salt and solvent may be 4 M of LiFSIdissolved in DME, to which the additives can be added. Table 1 indicatesa combination of polymer additive, cross-linker additive, and therelative concentrations that can be used of the polymer additive andcross-linker additive.

TABLE 1 Cross-Linker Polymer:Cross- Polymer Additive Additive Linker(g/L) P4VP (poly(4- C12TFSA 50:50 vinylpyridine)) P4VP C6TFSA 50:70PDMEMA (poly(2- C12TFSA 50:50 dimethylamino- ethylmethacrylate)) P4VPC12TFSA 50:50 PDMEMA C12TFSA 50:50 PDMEMA C12TFSA 100:50  PDMEMA C12TFSA40:50 P4VP C12TFSA 40:50

In some embodiments, one or more additional additives may also functionto reduce side reactions. A purpose of adding an additive can be to helpform LiF, namely solid electrolyte interphase (SEI), which can preventLi metal from having various side reactions.

While the lithium gel separator layer is in the form of dry separatorlayer 300, dry separator layer 300 may be layered with other batterycell layers in the place of lithium gel separator layer 130. Onceassembly of the battery cell's layers are complete and the battery cellhas been inserted into a housing (e.g., a pouch), a liquid electrolytemay be added, then heat and pressure may be applied.

At block 370 the liquid electrolyte mixture may be permeated into thenon-reactive scaffold. Arrow 315 represents that lithium liquid ispermeated throughout scaffolding material 305 to create lithiumliquid-permeated scaffolding material 320. The lithium liquid maypermeate the scaffolding material when left submerged at atmosphericpressure for a duration of time, such as between 6 hours and 24 hours.This step may be performed after the dry separator layer has beenassembled as part of a battery cell. The liquid electrolyte, which canbe a lithium liquid, may be composed of materials that after permeatinginto the voids within the scaffolding material and then subjected toheat, causing the lithium liquid at least partially solidify, such asinto a gel. Such an arrangement allows for a lithium gel separator layerto be initially created as a dry separator layer then for lithium liquidto be permeated throughout the scaffolding material and transitionedinto being a gel after the battery cell is housed within a housing(e.g., a pouch cell). In some embodiments, pressure is also applied, thepurpose of the pressure may be to crease the amount of contact atvarious interfaces within the layered stack.

After the lithium liquid has been permeated throughout scaffoldingmaterial 305 to create lithium liquid-permeated scaffolding material320, block 375 may be performed in which pressure, heat, or both may beapplied, as indicated by arrow 325. For instance, in some embodiments,pressure may first be applied at room temperature, at a force of 100N/cm² for a duration of between 60 and 120 seconds. A heat press processmay then be performed at a temperature of between 100° C.-110° C. at aforce of between 100-500 N/cm² for a duration of between 60 and 120seconds. The heat applied to lithium gel separator layer 301 may causelithium liquid-permeated scaffolding material 320 to transition intopseudo-solid lithium gel layer 330. In some embodiments, pressure mayassist the process or may help increase the surface area of interfacesbetween layers of the lithium gel separator layer and/or other layers ofthe battery cell. Lithium gel separator layer 302 may then be finallyformed.

To create such a battery cell, various methods may be performed. FIG. 4illustrates an embodiment of a method 400 for manufacturing apouch-style battery cell that contains an anode-free solid-state batteryhaving a lithium gel separator layer and an anti-dendrite layer. Atblock 405, an anti-dendrite layer may be layered onto an anode currentcollector. The anti-dendrite layer may be as detailed in relation toanti-dendrite layer 140 of FIG. 1. The anode current collector may be asdetailed in relation to anode current collector 150 of FIG. 1.

At block 410, a three-part lithium gel separator layer may be created.Initially the lithium gel separator layer may be in the form of a dryseparator layer. That is, liquid electrolyte, such as lithium liquid,has not yet been injected into the scaffolding layer as detailed inrelation to FIG. 3A. In other embodiments, the scaffolding material atblock 410 has been permeated with the liquid. The lithium gel separatorlayer, in which the lithium liquid may be present or not yet introduced,may be layered onto anti-dendrite layer at block 415. The amount ofadhesion between the lithium gel separator layer and the anti-dendritelayer may be greater than the amount of adhesion between theanti-dendrite layer and the anode current collector. In some instances,the amount of adhesion between the lithium gel separator layer and theanti-dendrite layer may be greater than the amount of adhesion betweenthe anti-dendrite layer and the anode current collector after theheating and pressing of block 430.

At block 420 the cathode layer may be layered onto the lithium gelseparator layer (of which the gel is still in the form of a liquid orhas not yet been introduced to the scaffolding material). At block 425,the cathode collector layer may be layered onto the cathode layer. Insome embodiments, block 425 may be performed, then the combined cathodeand cathode current collector layers may be layered onto the lithium gelseparator layer (of which the gel is still in the form of a liquid orhas not yet been introduced to the scaffolding material) at block 420.

It should be understood that blocks 405-425 may be repeated multipletimes to create multiple layer stacks for a solid state battery cell.For instance, 16 sets of layers may be created in a stack set similar todetailed in relation to FIG. 2. Such an arrangement allows for the anodecurrent collector and cathode current collector to be in contact withanti-dendrite layers and cathodes, respectively, on opposite sides.

At block 430, the one or more layer stacks may be packaged in a pouchcell. At this block, the lithium liquid (or other form of liquidelectrolyte), assuming it was introduced at block 410, may still be inliquid form. The layers stacks may be vacuum sealed within the pouchcell to remove excess air. The pouch cell may be made of a flexiblematerial, such as plastic, that can allow the pouch to expand and becompressed. If the lithium liquid was not permeated throughout thescaffolding layer at block 410, the lithium liquid may be introducedwithin the pouch cell when packaging is being performed (or before orafter) at block 432. The lithium liquid may then permeate into thescaffolding layer of the dry separator layer.

At block 435, one or more processes of heat, pressure, or both may beapplied to the packaged pouch cell. This process can perform multiplefunctions: 1) block 435 may increase the amount of physical contactbetween adjacent layers of the battery cell; 2) block 435 may cause thelithium liquid to convert to a lithium gel; and 3) block 435 may createadhesion between the anti-dendrite layers and the lithium gel layersthat is greater than the amount of adhesion between the anti-dendritelayers and the anode current collectors. For instance, in someembodiments, pressure may first be applied at room temperature, at aforce of between 80 and 120 N/cm² for a duration of between 60 and 120seconds. A heat press process may then be performed at a temperature ofbetween 80° C.-130° C. at a force of between 100-500 N/cm² for aduration of between 60 and 120 seconds.

At block 440, the pouch cell may be installed within a jig press (orsome other mechanical device that applies pressure to the pouch cell).The jig press may be used to apply long-term pressure to the SSB pouchcell. In some embodiments, multiple SSB pouch cells are layered and thencompressed using the jig press. While in the jig press, the SSB pouchcells may be repeated charged and discharged. The SSB pouch cells may beused to power a vehicle or some other form of electrically-powereddevice.

As an example of an SSB in accordance with FIG. 2 and that may bemanufactured according to method 400, an SSB pouch cell may be createdthat includes 16 layer sets and is approximately 65 mm by 65 mm. For agiven layer, at 0% SOC (state of charge) a thickness of 3.3 mm ispresent. At 100% SOC, a thickness of 3.64 mm is present, representingapproximately a 10% increase caused by swelling. The performance of theoverall cell may be 4520 mAh with an average voltage of 3.79 V. At 100%SOC, the energy density (by volume) may be 1122 Wh/L; the energy density(by weight), may be 432 Wh/Kg.

The above embodiments are focused on the creation of planar layers ofbattery cells. Such layers may be used in pouch-style battery cells. Inother embodiments, such as those detailed in relation to FIGS. 5 and 6,cylindrical battery cells may be created. Such cylindrical battery cellscan have the same layering as detailed in relation to FIGS. 1-3, howeverthe process to create the cylindrical cells may differ. Further detailregarding such embodiments is provided in relation to FIGS. 5 and 6.

FIG. 5 illustrates an embodiment of a cylindrical battery press system500. Cylindrical battery press system 500 can include: compressionmechanism 510; heating element 520; buffer material 530; cylindricalpouch battery cell (also referred to as “battery cell”) 540; temperaturesensor 550; support structure 560; and platform 570. Embodiments ofcylindrical battery press system and related systems are detailed inU.S. patent application Ser. No. 16/412,338, entitled “Isostatic PressDevices and Processes for Cylindrical Solid-State Batteries,” filed onMay 14, 2019, the entire disclosure of which is hereby incorporated byreference for all purposes. Other embodiments related to a system toisotropically pressurize a cylindrical battery cell are detailed in U.S.patent application Ser. No. 16/217,010, entitled “Hydraulic IsostaticPress Processes for Solid-State Batteries”, filed on Dec. 11, 2018, theentire disclosure of which is also hereby incorporated by reference forall purposes.

Compression mechanism 510 may be approximately cylindrical in shape andhave a cross-section that is similar to a halo. A gap along the curvedsidewall of compression mechanism 510 may be present. On either side ofthis gap is edge 511 and edge 512. By edge 511 being moved toward edge512, the volume within compression mechanism 510 may be decreased.Therefore, when edge 511 is away from edge 512, the volume withincompression mechanism is larger, allowing buffer material and/or batterycell 540 to be installed. When edge 511 is toward edge 512, the volumewithin compression mechanism 510 is smaller, thus applying pressure tobuffer material 530 and, through buffer material 530, to battery cell540.

Battery cell 540 may be a cylindrical jelly-roll style battery cell,such as one similar to the embodiments of FIGS. 1-3. The cylindricaljelly-roll style battery cell may (initially) be stored inside of apouch, which can be compressed using cylindrical battery press system500. After being compressed and heated using cylindrical battery presssystem 500, the cylindrical jelly-roll style battery cell may be removedfrom the pouch and installed within a cylindrical canister, such asdetailed in method 600 of FIG. 6.

Compression mechanism 510 may be formed from a semi-rigid material, suchas a hard rubber, plastic, or a layer of metal. Compression mechanism510 may be partially deformed by edge 511 being pushed or pulled towardedge 512. In some embodiments, edge 512 may be fixed to supportstructure 560. Edge 511 may be connected with an extension, such as ametal bar, that allows a user to manually push or pull the metal bar tomove edge 511 toward edge 512. In other embodiments, a hydraulic pump orelectric motor may be used to move edge 511 toward edge 512.

Buffer material 530 may be wrapped around battery cell 540. Buffermaterial 530 may be a semi-rigid material, such as heat resistantrubber. In some embodiments, buffer material 530 may be a rubber orother form of flexible skin that is filled with liquid. Buffer material530, when viewed as a cross-section, may generally be halo-shaped. Thishalo shape defines a void within its center, into which a battery cellcan be placed. Buffer material 530 may serve to transfer pressureapplied by compression mechanism 510 to battery cell 540. Buffermaterial 530 may help distribute the pressure applied by compressionmechanism 510 such that the pressure applied to the curved sidewall ofbattery cell 540 is uniform or nearly uniform. In some embodiments,buffer material 530 is first wrapped around battery cell 540. In someembodiments, buffer material 530 may be a sheet of buffer material inwhich battery cell is rolled. Therefore, the jelly-roll style batterycell may, in turn, be within a jelly-roll of buffer material. Buffermaterial 530 may be installed with compression mechanism 510.

Between buffer material 530 and compression mechanism 510, heatingelement 520 may be present. Heating element 520 may be generallycylindrical in shape and may have a gap along the curved sidewall thatmatches the gap of compression mechanism 510. Heating element 520 may bea resistive heater such that when current is applied to heating element520, heat is generated. In some embodiments, heating element 520 iscapable of heating up to 250° C. The amount of heat output by heatingelement 520 may be controlled based on the output of temperature sensor550. Temperature sensor 550 may be located between battery cell 540 andbuffer material 530. Therefore, temperature sensor 550 may indicate thetemperature at an external surface of battery cell 540. In someembodiments, it may be desirable for battery cell 540 to be heated tobetween 80° C. and 120° C. By applying a greater temperature usingheating element 520, it may be possible for battery cell 540 to beheated to between 80° C. and 120° C. at its surface quicker. An externalheating controller (not pictured) may receive temperature measurementsfrom temperature sensor 550 and control the amount of heat generated byheating element 520.

While edge 512 is fixed to support structure 560, which is in turn fixedto platform 570, edge 511 may remain free. By edge 511 remaining freefrom support structure 560 and platform 570, edge 511 may be movedtoward edge 512, thus slightly deforming compression mechanism 510. Whenforce is ceased to be applied to edge 511, compression mechanism 510 mayexpand back to a natural shape and pressure may cease being applied tobattery cell 540. It should be understood that the force applied to edge511 may be applied in the vicinity of edge 511 and not necessarilyprecisely on edge 511. However, the closer such force is applied to edge511, the more evenly distributed the pressure applied to buffer material530 may be. Similarly, it should be understood that edge 512 can bedirectly fixed to support structure 560, but rather a portion ofcompression mechanism 510 in a vicinity of edge 512 may be fixed tosupport structure 560. Again here, the portion of compression mechanism510 to edge 512 fixed to support structure 560, the more evenlydistributed the pressure applied to buffer material 530 may be.

To create a cylindrical battery cell, various methods may be performed.FIGS. 6A and 6B illustrates an embodiment of a method for creating acylindrical anti-dendrite anode-free solid-state battery. In block605-620, various steps may be performed to create a layered stacksimilar to as presented in and described in relation to FIG. 1. In otherembodiments, blocks 605-620 may be performed to create a stack set asdetailed in relation to FIG. 2. That is, blocks 605-620 may be performedmultiple times to two or more (e.g., 3-20) sets of layers.

Blocks 605-620 represent a possible embodiment of how multiple layersmay be stacked together. In other embodiments, the ordering of blocks605-620 may be different. At block 605, a cathode layer may be attachedto a cathode current collector layer. The cathode current collectorlayer may be aluminum foil and the cathode may, for example, be NCA(Nickel-Cobalt-Aluminum Oxide) or NCM (nickel-manganese-cobalt). Thecathode layer may be deposited onto the cathode current collector layeror the cathode current collector layer may be deposited onto the cathodelayer.

At block 610, an anti-dendrite layer may be deposited onto or otherwiseattached with an anode current collector layer. The anode currentcollector layer may be copper and the anti-dendrite layer may be carbonblack; acetylene back black; silver; zinc; gold; bismuth; tin;polyvinylidene fluoride (PvDF); polymide (PI); polyacrylic acid (PAA);and carboxymethyl cellulose styrene-butadiene rubber (CMC-SBR). Theanti-dendrite layer may also be formed using alloys of silver, zinc,gold, bismuth, and tin. The anti-dendrite layer may serve to decreasethe nucleation energy for lithium ions to deposit onto a surface of theanode current collector layer.

At block 615, a dry separator layer, such as dry separator layer 300,may be attached to either the cathode layer or the anti-dendrite layeror otherwise positioned between them. The dry separator layer caninclude two adhesive layers and a scaffolding material, such as detailedin relation to dry separator layer 300. At block 620, a layered stackmay be created that includes the dry separator layer being layeredbetween the cathode and the anti-dendrite layer. The layered stack mayinclude at least: the dry separator layer, the anti-dendrite layer, theanode current collector layer, the cathode layer, and the cathodecurrent collector layer, such as illustrated to FIG. 1 (with the dryseparator layer in lieu of the lithium-gel separator layer.

At block 625, the layered stack may be rolled onto itself multiple timesto create a jelly-roll style battery cell. When the layers are rolledtogether, a roughly cylindrical rolled layered stack can be created. Atblock 630, the rolled layered stack may be inserted within acompressible, flexible pouch. The pouch may serve as a temporary housingfor the battery cell during a portion of the manufacturing process.Prior to sealing the pouch, an electrolyte solution may be injected oradded into the pouch. The electrolyte solution may be the lithium liquidmay be as detailed in relation to FIG. 3A. The injection of the lithiumliquid may cause the scaffolding material of the dry separator layer tobe permeated by the lithium liquid and become lithium-liquid permeatedscaffolding material, such as lithium-liquid permeated scaffoldingmaterial 320. As part of block 635, the pouch may have any air presentremoved and may be sealed.

At block 640, pressure may be applied to the pouch. The pressure may beapplied using a system similar to cylindrical battery press system 500.Prior to pressure being applied, a temperature probe may be insertedsuch that the temperature probe is adjacent to an external surface ofthe pouch within the cylindrical battery press system. Pressure may thenbe applied by the cylindrical battery press system either manually orusing a motorized or hydraulic embodiment. The pressure applied may bebetween 100 kPa and 100 MPa. In some embodiments, pressure is appliedfor between 30 seconds and 1 hour.

At block 645, which may be performed at the same time as block 640 or atleast partially overlapping in time with block 640, heat may be applied.The amount of heat applied may be between 150° C. and 250° C. Thetemperature of the pouch may be monitored using the temperature probe.Heat may be applied until the battery cell is between 60° C. and 150° C.for a period of time, such as between 30 seconds and 1 hour. Thepressure, heat, or both may cause the lithium liquid that permeates thescaffolding layer to transition to being a pseudo-solid lithium gellayer. Therefore, no liquid remains within the pouch. Accordingly, thebattery cell is a solid-state battery cell (that includes a gel).

The heat and pressure applied at blocks 640 and 645 may additionally oralternatively increase the amount of surface area contact between one ormore of the layers of the battery cell. Additionally or alternatively,the heat and pressure may increase the adhesion among two or more of thelayers of the battery cell.

At block 650, the cylindrical jelly roll that has been subjected to theheat and pressure may be removed from the pouch. No liquid may bepresented because it has transitioned into a gel within the scaffoldinglayer. The cylindrical jelly roll may be inserted into a cylindricalbattery cell canister. The cylindrical battery cell canister may berigid or semi-rigid. In some embodiments, the cylindrical battery cellcanister may be metal. The cylindrical battery cell canister may exertpressure on the cylindrical jelly roll when the cylindrical jelly rollexpands. For example, when the battery cell is charged at block 660,lithium deposition on the anode current collector can cause the batteryto swell 0.5% to 3% in diameter. Pressure exerted by the sidewalls ofthe cylindrical battery cell canister can help control the amount ofswelling and help keep layers of the battery cell in contact with eachother. At block 660, the battery cell may repeatedly be charged anddischarged to power an electric device, such as an electric vehicle(EV). A cylindrical battery manufactured according to method 600 may becharged to 7559 Ah, may discharge 6229 Ah, thus exhibiting an initialColumbic efficiency of 82.4%.

When lithium deposits on an anode-current collector during charging, itmay tend to deposit in pools, rather than in a roughly flat film. Sincethe amount of contact present between the deposited lithium and theanode current collector can be small, the electrical connection betweenthe deposited lithium and the anode current collector may be small.Having a small or weak electrical connection between the depositedlithium and the anode current collector can cause the impedance of thebattery cell to be high. A high impedance can result in reducedperformance of the battery cell: that is, a battery with a low internalresistance may be able to deliver a large amount of current on demand.For some applications, like use in an electric vehicle (EV), the abilityto delivery current quickly can greatly affect performance, such as theability of the EV to accelerate. When a battery cell has a high internalresistance, current flowing through the battery cell can cause thebattery to heat up, which can damage the battery cell.

In some embodiments, an additional layer may be present within the layerstack of an anode-free solid-state battery. The additional layer may besituated between the anti-dendrite layer and the anode currentcollector. This layer can be referred to as an interfacial bondinglayer. The interfacial bonding layer may encourage formation of lithiumdeposits with a high degree of surface contact between the interfacialbonding layer and the lithium deposits. Since the interfacial bondinglayer has a large amount of contact with both the anode currentcollector and deposited lithium, the internal resistance of the batterycell can be decreased. Such an interfacial bonding layer may be added toany of the embodiments detailed in relation to FIGS. 1-6 or as detailedin relation to FIGS. 7-10.

An interfacial layer may be made from conductive agents and binder. Insome embodiments, the interfacial layer may be between 30%-99%conductive agent; the remainder of the interfacial bonding layer may bebinder (1%-70%). FIG. 7 illustrates an embodiment of a layer stack 700of an anode-free solid-state battery having a lithium gel separatorlayer, an anti-dendrite layer, and a interfacial bonding layer. Layerstack 700 may be as detailed in relation to

FIG. 1., however interfacial bonding layer 710 may be presented betweenanode current collector 150 and anti-dendrite layer 140. Interfacialbonding layer 710 may be in direct contact on a first side withanti-dendrite layer 140 and in direct contact on a second, opposite sidewith anode current collector 150.

In order to encourage deposition of lithium metal on interfacial bondinglayer 710, interfacial bonding layer 710 may have a first amount ofadhesion with anode current collector 150 that is greater than a secondamount of adhesion between anti-dendrite layer 140 and interfacialbonding layer 710 or a third amount of adhesion between anti-dendritelayer 140 and Lithium gel separator layer 130. The thickness ofinterfacial bonding layer 710 may be between 0.05 μm and 5 μm. Thedensity of the interfacial bonding layer may be between 0.1 and 2.0grams per cubic centimeter.

Interfacial bonding layer 710 may use carbon as a conductive agent mixedwith binders (PvDF, SBR-CMC, PAA) and metal particles such as Bi, Sn,Ag, Au, Pt. More specifically, acetylene black or carbon black may beused as the conductive agent. The individual carbon particles may bebetween 3 nm and 20 nm spherical shape particles. Possible types ofbonders include: PvDF, SBR-CMC, and PAA.

The impedance or resistance of the battery cell of FIG. 7, as measuredbetween terminal 720 and terminal 730 may be significantly decreased bythe presence of interfacial bonding layer 710 as compared to anembodiment, such as FIG. 1, where interfacial bonding layer 710 is notpresent. As an example, an embodiment of a battery cell without aninterfacial bonding layer may have an impedance of 0.85 ohms; but if aninterfacial bonding layer is present between the anode current collectorand the anti-dendrite layer, the impedance may be 0.05 ohms.

FIG. 8 illustrates an embodiment of a layer stack 800 of an anode-freesolid-state battery that indicates relative amounts of adhesion betweenvarious layers. One of the key aspects of layer stack 700 of FIG. 7 maybe that that the relative amount of adhesion between the layersencourages lithium metal to plate during the charging process betweenanti-dendrite layer 140 and interfacial bonding layer 710.

Interface 801 between lithium gel separator layer 130 and anti-dendritelayer 140 may have a first amount of adhesion. Interface 802 betweenanti-dendrite layer 140 and interfacial bonding layer 710 may have asecond amount of adhesion. Interface 803 between interfacial bondinglayer 710 and anode current collector 150 may have a third amount ofadhesion. By interface 802 having less adhesion than interface 801 orinterface 803, lithium may be encouraged to plate at interface 802.Stated another way, the second amount of adhesion may be greater thanthe first amount of adhesion or the third amount of adhesion.

FIG. 9 illustrates an embodiment 900 of a layer stack of an anode-freesolid-state in which lithium ions migrate and are deposited onto theinterfacial bonding layer. In embodiment 900, the battery cell is beingcharged. Charging causes lithium ions to migrate from cathode 120,through lithium gel separator layer 130, through anti-dendrite layer 140and plate as lithium metal layer 910 between anti-dendrite layer 140 andinterfacial bonding layer 710, as indicated by arrows 905. Anti-dendritelayer 140 may help inhibit the growth of dendrites that could piercelithium gel separator layer 130. Therefore, interfacial bonding layer710 may be used in conjunction with anti-dendrite layer 140.

The presence of lithium metal layer 910 may cause swelling in thebattery cell. During a discharge cycle, lithium ion may migrate fromlithium metal layer 910 to cathode 120. Swelling within the battery cellmay decrease as the battery cell is discharged and lithium ions migrateto cathode layer 120.

FIG. 10 illustrates an embodiment of a method 1000 for manufacturing apouch-style battery cell that contains a solid-state battery having alithium gel separator layer, an anti-dendrite layer, and an interfacialbonding layer. It should be understood that method 1000 can be adaptedin accordance with the blocks of method 600 of FIGS. 6A and 6B such thata interfacial bonding layer can be manufactured as part of a cylindricalbattery cell.

At block 1005, an interfacial bonding layer can be deposited onto theanode current collector. The anode current collector may be as detailedin relation to anode current collector 150 of FIG. 1. Block 1005 caninclude a conductive material, such as acetylene black, being mixed witha bonder and deposited onto the anode current collector.

At block 1010, a three-part lithium gel separator layer may be created.Initially the lithium gel separator layer may be in the form of a dryseparator layer. That is, liquid electrolyte, such as lithium liquid,has not yet been injected into or permeated throughout the scaffoldinglayer as detailed in relation to FIG. 3A. In other embodiments, thescaffolding material has been permeated with the liquid. Ananti-dendrite layer may be layered onto the lithium gel separator layer,in which the lithium liquid (or another liquid electrolyte) may bepresent or not yet introduced at block 1020. The anti-dendrite layer maybe as detailed in relation to anti-dendrite layer 140 of FIG. 1. In someinstances, the amount of adhesion between the lithium gel separatorlayer and the anti-dendrite layer may be greater than the amount ofadhesion between the anti-dendrite layer and the interfacial bondinglayer.

At block 1025 the cathode layer may be layered onto the lithium gelseparator layer (of which the gel is either still in the form of aliquid or not yet present). At block 1030, the cathode collector layermay be layered onto the cathode layer. In some embodiments, block 1030may be performed, then the combined cathode and cathode currentcollector layers may be layered onto the lithium gel separator layer atblock 1025.

At block 1032, the anti-dendrite layer that was previously layered ontothe lithium-gel separator layer may have its opposite side layerslayered onto the interfacial bonding layer. The layering of theanti-dendrite layer and the interfacial bonding layer may result inrelatively little adhesion being present between the layers. Theanti-dendrite layer may create an interface that has less adhesion withthe interfacial bonding layer than the interfacial bonding layer formswith the anode current collector. The amount of adhesion can becontrolled by modulating the binder and active conductive material ratioof the interfacial bonding layer. For example, PvDF may be used as thebinder and ketchen black may be used as the active material in a ratioof 3% PvDF to 97% ketchen black. In other embodiments, the ration ofketchen black is between 95% and 98%.

It should be understood that blocks 1005-1030 may be repeated multipletimes to create multiple layer stacks for a solid state battery cell.For instance, 16 sets of layers may be created in a stack set similar todetailed in relation to FIG. 2 with the addition of interfacial bondinglayers. Such an arrangement allows for the anode current collector andcathode current collector to be in contact with anti-dendrite layers andcathodes, respectively, on opposite sides.

At block 1035, the one or more layer stacks may be packaged in a pouchcell. At this block, the lithium liquid (or other form of liquidelectrolyte), assuming it was introduced at block 1015, may still be inliquid form. The layers stacks may be vacuum sealed within the pouchcell to remove excess air. The pouch cell may be made of a flexiblematerial, such as plastic, that can allow the pouch to expand and becompressed. If the liquid electrolyte, such as lithium liquid was notpermeated throughout the scaffolding layer at block 1015, the liquidelectrolyte may be introduced within the pouch cell when packaging isbeing performed (or before or after) at block 1040. The lithium liquidmay then permeate into the scaffolding layer of the dry separator layer.

At block 1045, one or more processes of heat, pressure, or both may beapplied to the packaged pouch cell. This process can perform multiplefunctions: 1) block 1045 may increase the amount of physical contactbetween adjacent layers of the battery cell; 2) block 1045 may cause theliquid electrolyte (e.g., lithium liquid) to convert to a lithium gel;and 3) block 1045 can help create adhesion between the interfacialbonding layers and the anode current collectors that is greater than theamount of adhesion between the anti-dendrite layers and the interfacialbonding layers. For instance, in some embodiments, pressure may first beapplied at room temperature, at a force of between 80 and 120 N/cm² fora duration of between 60 and 120 seconds. This portion of the processmay increase the amount of contact present at one of more interfaces ofthe layers of the battery cell. A heat press process may then beperformed at a temperature of between 50° C.-130° C. at a force ofbetween 100-1000 N/cm² for a duration of between 60 and 2400 seconds.

At block 1050, the pouch cell may be installed within a jig press (orsome other mechanical device that applies pressure to the pouch cell).The jig press may be used to apply long-term pressure to the SSB pouchcell. In some embodiments, multiple SSB pouch cells are layered and thencompressed using the jig press. While in the jig press, the SSB pouchcells may be repeated charged and discharged. The SSB pouch cells may beused to power a vehicle or some other form of electrically-powereddevice.

The methods, systems, and devices discussed above are examples. Variousconfigurations may omit, substitute, or add various procedures orcomponents as appropriate. For instance, in alternative configurations,the methods may be performed in an order different from that described,and/or various stages may be added, omitted, and/or combined. Also,features described with respect to certain configurations may becombined in various other configurations. Different aspects and elementsof the configurations may be combined in a similar manner. Also,technology evolves and, thus, many of the elements are examples and donot limit the scope of the disclosure or claims.

Specific details are given in the description to provide a thoroughunderstanding of example configurations (including implementations).However, configurations may be practiced without these specific details.For example, well-known processes, structures, and techniques have beenshown without unnecessary detail in order to avoid obscuring theconfigurations. This description provides example configurations only,and does not limit the scope, applicability, or configurations of theclaims. Rather, the preceding description of the configurations willprovide those skilled in the art with an enabling description forimplementing described techniques. Various changes may be made in thefunction and arrangement of elements without departing from the spiritor scope of the disclosure.

Also, configurations may be described as a process which is depicted asa flow diagram or block diagram. Although each may describe theoperations as a sequential process, many of the operations can beperformed in parallel or concurrently. In addition, the order of theoperations may be rearranged. A process may have additional steps notincluded in the figure.

Having described several example configurations, various modifications,alternative constructions, and equivalents may be used without departingfrom the spirit of the disclosure. For example, the above elements maybe components of a larger system, wherein other rules may takeprecedence over or otherwise modify the application of the invention.Also, a number of steps may be undertaken before, during, or after theabove elements are considered.

What is claimed is:
 1. An anti-dendrite anode-free solid-state battery,comprising: a cathode layer; an anode current collector layer; a lithiumgel separator layer between the cathode layer and the anode currentcollector layer; and an anti-dendrite layer located between the lithiumgel separator layer and the anode current collector layer, wherein theanti-dendrite layer discourages dendrite formation.
 2. The anti-dendriteanode-free solid-state battery of claim 1, wherein the lithium gelseparator layer comprises: a first adhesive layer; a second adhesivelayer; and a lithium gel layer located between the first adhesive layerand the second adhesive layer.
 3. The anti-dendrite anode-freesolid-state battery of claim 2, wherein the lithium gel layer comprises:a scaffolding material; a salt; a solvent; and at least one additive. 4.The anti-dendrite anode-free solid-state battery of claim 3, wherein theat least one additive comprises a polymer and a cross-linker.
 5. Theanti-dendrite anode-free solid-state battery of claim 3, wherein thefirst adhesive layer and the second adhesive layer comprises alithium-conductor ceramic.
 6. The anti-dendrite anode-free solid-statebattery of claim 1, wherein a presence of the anti-dendrite layer causesa nucleation barrier to be decreased in energy for lithium ions todeposit onto the anode current collector layer.
 7. The anti-dendriteanode-free solid-state battery of claim 6, wherein the anti-dendritelayer is between 0.05 micrometers and 10 micrometers in thickness. 8.The anti-dendrite anode-free solid-state battery of claim 7, wherein theanti-dendrite layer comprises one or more materials selected from thegroup consisting of: carbon black; acetylene black; ketchen black;silver; zinc; gold; bismuth; tin; polyvinylidene fluoride (PVDF);polymide (PI); polyacrylic acid (PAA); and carboxymethyl cellulosestyrene-butadiene rubber (CMC-SBR).
 9. The anti-dendrite anode-freesolid-state battery of claim 8, wherein a first amount of adhesionbetween the anti-dendrite layer and the anode current collector layer isless than a second amount of adhesive between the anti-dendrite layerand the lithium gel separator layer.
 10. The anti-dendrite anode-freesolid-state battery of claim 9, wherein the anode current collectorlayer is copper.
 11. The anti-dendrite anode-free solid-state battery ofclaim 1, further comprising an aluminum cathode current collector.
 12. Amethod for creating an anti-dendrite anode-free solid-state battery, themethod comprising: depositing an anti-dendrite layer onto an anodecurrent collector layer; creating a lithium-gel separator layer;layering a cathode current collector layer onto a cathode layer;layering the lithium-gel separator layer between the anti-dendrite layerand the cathode layer, thereby creating a layered battery stack of: thecathode current collector layer, the cathode layer, the lithium-gelseparator layer, the anti-dendrite layer, and the anode currentcollector layer; packaging the layered battery stack in a flexible pouchcell; and applying heat and pressure to the layered battery stack withinthe flexible pouch cell.
 13. The method for creating the anti-dendriteanode-free solid-state battery of claim 12, wherein creating thelithium-gel separator layer comprises: attaching a first adhesive layerto a scaffolding; attaching a second adhesive layer to the scaffolding;and permeating a liquid electrolyte into the scaffolding.
 14. The methodfor creating the anti-dendrite anode-free solid-state battery of claim13, wherein the liquid electrolyte comprises: a lithium salt; a solvent;and at least one additive.
 15. The method for creating the anti-dendriteanode-free solid-state battery of claim 14, wherein the at least oneadditive comprises a polymer and a cross-linker.
 16. The method forcreating the anti-dendrite anode-free solid-state battery of claim 15,wherein applying the heat causes the liquid electrolyte to become a gel.17. The method for creating the anti-dendrite anode-free solid-statebattery of claim 12, wherein a presence of the anti-dendrite layercauses a nucleation barrier to be decreased in energy for lithium ionsto deposit onto the anode current collector layer.
 18. The method forcreating the anti-dendrite anode-free solid-state battery of claim 17,wherein the anti-dendrite layer is between 0.05 micrometers and 10micrometers in thickness.
 19. The method for creating the anti-dendriteanode-free solid-state battery of claim 12, further comprising:compressing the flexible pouch cell in a jig press; and charging anddischarging the layered battery stack within the jig press.
 20. Themethod for creating the anti-dendrite anode-free solid-state battery ofclaim 12, wherein the anti-dendrite layer comprises one or morematerials selected from the group consisting of: carbon black; acetyleneblack; ketchen black; silver; zinc; gold; bismuth; tin; polyvinylidenefluoride (PVDF); polymide (PI); polyacrylic acid (PAA); andcarboxymethyl cellulose styrene-butadiene rubber (CMC-SBR).